PARIS -- French prosecutors are investigating a cryptic e-mail sent to an Islamic Web site urging attacks on the capital's mayor and its tourist sites, judicial officials said Wednesday.

The e-mail's sender and the site were not identified by the officials, who spoke on condition of anonymity because they were not authorized to discuss the matter publicly. They said only that the message went to an Internet site run by Salafists, or Islamic fundamentalists.

Paris Mayor Bertrand Delanoe said on RTL radio that authorities informed him of the threat Saturday.

"I am calm. I have the information I need and I have complete confidence in the work ... of police headquarters vis-a-vis security problems in general, terrorism in particular and finally the protection of the mayor of Paris," Delanoe said later on the TV station iTele.

The anti-terrorism section of the Paris prosecutor's office is overseeing the investigation by the French counterespionage agency known as the DST, the judicial officials said.